Nuclear
Reaction : A reaction in which there is a successful attempt
by an external bombarding particle to change the content of
a nucleus is known as a nuclear reaction.

Non-Uniform
Magnetic Field : The magnetic field in a region is non-uniform
if the magnitude or/and direction of magnetic flux density
varies from point to point in the region.

Natural Points : A point near a magnet where the magnetic
field due to the magnet is completely neutralized by the horizontal
component of earth's magnetic field is called a natural point.

Nuclear
Mass : The total mass of nucleons in the nucleons in the
nucleus is called nuclear mass i.e. Nuclear Mass, A = Mass
of protons + Mass of neutrons.

Nuclear
Forces : The strong forces of attraction which firmly
hold the nucleons in the nucleus are known as nuclear forces.

Nuclear
Binding Energy : The total energy required to liberate
all the nucleons from the nucleus (i.e. to disintegrate the
nucleus completely into its constituent particles) is called
nuclear binding energy of the nucleus.

Natural
Radioactivity : The process of spontaneous (i.e. without
external means, by itself) disintegration of the nuclei of
heavy elements with the emission of certain type of radiation
is known as natural radioactivity.

Nuclear
Reactor : A nuclear reactor is a device in which controlled
fission chain reaction take place. A nuclear reactor is also
known as nuclear pile or atomic pile.

Nuclear
Fusion : The process of combining two light nuclei to
form a heavy nucleus with the release of huge amount of energy
is known as nuclear fusion.

n-Type
Semiconductor : When a small amount of pentavalent impurity
is added to a pure semiconductor, it is known as n-type semiconductor.